For many years, powered line or blade-type trimmers have been offered for the trimming and weeding of lawns in the horizontal plane. Similarly, powered edgers have been offered for the cutting of lawns away from walkways and driveways in the vertical plane.
Consumers, in their desire to purchase and utilize only one tool for these equivalent lawn cutting purposes, have attempted to use trimmers of the aforementioned type, intended for use in a horizontal position for grass and weed cutting purposes, in a rotated, vertical plane to function as a lawn edger.
Most of these units have a control handle, containing the power switches, and an accessory handle, for additional support of the unit's weight and for use in maneuvering the unit in use. Disadvantageously, however, due to the designs of these handles, many units are not convenient or safe to use in such a way. Often only a single accessory handle position is provided, optimized for use in the lawn cutting horizontal plane. Accordingly, when the device is held in the edging position, the accessory handle is generally in an inconvenient and off-balance position.
Further contributing to the inconvenience in use of such devices in the vertical plane edging position, the on/off switch and the activation trigger has been located in an inconvenient position. A switch or trigger that is not in a convenient position raises the dual concerns that the device might be started by accident, resulting in a device that is both difficult to use and unsafe, or might be difficult to stop in an emergency situation.
Recent units have been developed that make it more convenient and comfortable for the operator of the unit to more easily hold the unit in the required vertical edging position. Some such units have devices provided for the rotation of the trimmer head about its shaft, in effect allowing rotation of the cutting plane. Often, however, such rotation devices are cumbersome and inconvenient to use.
For edging use, in addition to the issue of maintaining an adequate control position, devices have been developed to help guide the trimmer with a consistent motion, so as to give the trimmed edge a neat appearance. Many such devices of this type comprise wheel-and-bracket arrangements, rubbing pads, or wire guide loops, configured to hold the trimmer at a relatively uniform height.
Many such devices have been developed to safely hold the trimmer in an edging position, and to guide the trimmer in a linear motion, so as to give the trimmed edge a neat appearance. Most of these are of an A-frame type, with wheels mounted on the frame and the frame clamped to the shaft of the trimmer. Some of these types of devices allow the user to loosen the clamp and rotate the trimmer into an edger position. U.S. Pat. No. 4,922,694 to Emoto and U.S. Pat. No. 5,450,715 to Murray are examples of this kind of device. Some of these devices, such as U.S. Pat. No. 4,224,784 to Hansen et al. have the wheels rotated 90 degrees to function as an edge guide. Still other designs have plates clamped to the shaft which held wheels in an edging configuration, such as in U.S. Pat No. 4,981,012 to Claborn. Other devices, such as U.S. Pat. No. 5,228,276 to Miller, are merely axles which bolt to the trimmer.
Through the additional use of a vertical-plane feature in association with these devices, the orientation of the cutting plane to the adjacent vertical curbing surface can be controlled in a more consistent manner. Unfortunately, these devices are sometimes unwieldy to install, to use, and to store. Such devices do not provide a single tool solution to the problem identified by many consumers.
It is, therefore, readily apparent that there is a need for a, new and improved combination line trimmer and edging device, further providing, in a preferred embodiment, two equally-convenient operating and control positions, a flanged roller edge guide, and dual-action safety switches symmetrically located about the shaft of the device; and, in an alternate embodiment, the above features including a battery located symmetrically in-line with the center of the shaft of the device.
It is, therefore, to the provision of such an improved device that the present invention is directed.